Land-based seismic data acquisition and processing techniques are used to generate a profile (image) of a geophysical structure (subsurface) of the underlying strata. This profile does not necessarily provide an accurate location for oil and gas reservoirs, but it may suggest, to those trained in the field, the presence or absence of oil and/or gas reservoirs. Thus, providing an improved image of the subsurface in a shorter period of time is an ongoing process.
The acquisition of data in land-based seismic methods usually produces different results in source strength and signature based on differences in near-surface conditions. Further data processing and interpretation of seismic data requires correction of these differences in the early stages of processing. Surface-consistent amplitude and deconvolution are commonly used in seismic time processing to correct a portion of the distortions generated by the near-surface irregularities on the recorded seismic data. In another aspect, the near-surface irregularities generate both amplitude decay and a more complicated frequency-dependent time-varying filtering effect.
A conventional approach of processing for the computation of surface consistent amplitude and deconvolution corrections is based on a two-step cascaded process. The first step of the cascaded process comprises computing the amplitude scalar i.e., the surface-consistent amplitude correction, for application to the seismic data. The second step of the cascaded process comprises computing a deconvolution operator on the amplitude corrected pre-stack data. Of note in the two-step cascaded process is the fact that usually different algorithms are used for the amplitude and deconvolution calculations even though the calculations involve the same set of assumptions and theories. The two processes are separately estimated because the amplitude scalars cannot be directly derived from the autocorrelation spectra during the deconvolution step itself.
Historically, the surface consistent concept and estimating residual statics was introduced by M. T. Tanner, F. Koelher and K. A. Alhilali in their 1974 article entitled “Estimation and Correction of Near-Surface Time Anomalies” published in Geophysics. Next, the surface-consistent concept was extended to deconvolution by M. T. Tanner and K. W. Coburn in their 1980 paper entitled “Surface Consistent Estimation of Source and Receiver Response Functions,” presented at the 50th Annual International Meeting of the Society of Exploration Geophysicists. Then, the surface consistent deconvolution was refined with the addition of an average response factor, depending mainly on the average shot waveform by L. Morley and J. Claerbout in their 1983 article entitled “Predictive Deconvolution in Shot-Receiver Space” published in Geophysics. Next, the advantages of surface-consistent deconvolution as a means to obtain better statistical estimates of the filters was illustrated by S. Levin in his 1989 article entitled “Surface-Consistent” published in Geophysics.
Further, improvements related to robustness in the presence of noise as described by X. Wang, A. Chaney, M. Martin and M. Perz in their 2000 paper entitled “Surface Consistent Deconvolution on Seismic Data with Surface Consistent Noise” presented at the 2000 Meeting of the Canadian Society of Exploration Geophysicists, improving behavior in the long wavelengths by J. Millar and J. C. Bancroft in their 2006 paper entitled “Long Wavelength Solutions to the Surface Consistent Equations” published in the Society of Exploration Geophysicists Expanded Abstracts and using the reciprocity of the medium response by R. Van Vossen, A. Curtis, A. Laake and J. Tramped in their 2006 article entitled “Surface Consistent Deconvolution using Reciprocity and Waveform Inversion” published in Geophysics. Regarding the surface-consistent amplitude evolution, a performance factor as the natural logarithm of the average amplitude spectrum of the response function was introduced by M. T. Tanner and F. Koelher in their 1981 article entitled “Surface Consistent Corrections” published in Geophysics.
Accordingly, it would be desirable to provide systems and methods that avoid the afore-described problems and drawbacks, and improve the accuracy of the final image.